另一个嵌套循环php + mysql查询

Question

I have searched this for hours and read numerous q/a's on foreach loops and while loops for the answer to my question but have yet to find a response that resembled my query. Mostly categorized menues...

I have a mysql table setup like this

cat | product | link  | status
1   | milk    | https | in stock
1   | eggs    | https | in stock
2   | butter  | https | out of stock
2   | bread   | https | in stock
3   | bananas | https | in stock 

and would like to group the data in a php looped table like this;

         Category 1
 milk    | https | in stock
 eggs    | https | in stock
         Category 2
 butter  | https | out of stock
 bread   | https | in stock
         Category 3
 bananas | https | in stock 

What sort of nested loop would I need? would I need to call a second mysqli query in the nested loop grouping rows by cat ?

Thanks :)

PHP code added Edit

$stmt = $con->prepare("SELECT * FROM wp_products ORDER BY cat");
$stmt->execute();

$results = $stmt->get_result();
echo "<p><center><h4>Master List</h4></center></p>";
echo "<table>
<tr>
<th>Product</th>
<th>Link</th>
<th>Status</th>
</tr>";
if (mysqli_num_rows($results)>0){
while($row = $results->fetch_assoc())
{
  echo "<tr><td>" . $row['product'] ."</td>";
  echo "<td>". $row['link'] ."</td>;
  echo "<td>". $row['status'] ."</td></tr>";
}
}
echo "</table>";

Answer 1

Mostly it will be like the below.

The idea is

1. Sort the rows with category. [you have done this part.]
2. Declare the category with a default value.
3. If there is any change, update the category value with new one. [as it is sorted, it will always grouped by default. ]

The code will be like this.

<?php

$stmt = $con->prepare("SELECT * FROM wp_products ORDER BY cat");
$stmt->execute();

$category = '';  # Default value for category. 

$results = $stmt->get_result();
echo "<p><center><h4>Master List</h4></center></p>";
echo "<table>
<tr>
<th>Product</th>
<th>Link</th>
<th>Status</th>
</tr>";
if (mysqli_num_rows($results) > 0) {
   while ($row = $results->fetch_assoc()) {

      # Category will be updated in this query 
      if($category != $row['cat']) { 
         $category = $row['cat']; 
         echo '<tr><td colspan="3"> Category ' . $category .' </td></tr>'; 
      }

      echo "<tr><td>" . $row['product'] . "</td>";
      echo "<td>" . $row['link'] . "</td>";
      echo "<td>" . $row['status'] . "</td></tr>";
   }
}
echo "</table>";

Check on. :)